Eye-testing device



Patented May 15, 1928.

v UNITED STATES J'OSEPH W. SMITH, OF CAMBRIDGE, OHIO.

EYE-TESTING DEVICE.

Application filed March 16, 1925. Serial No. 16,000.

The present invention relates to a method of and. apparatus for thetesting of eyesight and more particularly to an apparatus suitable'fordetecting the state of the external ocular muscles and for determiningthe amount of the insu'fiiciencies thereof. a It is also adapted fordetermining and measuring ametropia binocularly. The present device isadapted to allow both eyes to be refracted at the same time and alsoenables the operator to keep the state of particular ocular musclesunder observation throughout the entire test with lenses and prisms.Briefly stated, the present improved device is designed to test the eyesof a patient by wholly retaining singleness of the test object, orchart, and in contradistinction to the usual type of tests, it preservesthe similarity of the test image in either or both eyes. The principleof the present invention, so far as itrelates to the testing of muscularimbalance, is to present a separate image from each eye which, may becarried along the nerve fibers to the brain so that when united, asingle image will be presented if the eyes are orthophoric; whereas, incase 'the eyes are not in normal balance, the two images from the twoeyes will not make a single image in the brain and the amount of suchimbalance can readily be determined, as Well as'whether the imbalance hevertical or horizontal.

To the accomplishment of the foregoing and related ends, the inventionthen consists of the steps and means hereinafter fully described andparticularly set forth in the claims, the annexed. drawing and thefollowing description set forth in detail certain means and one modeofcarrying out the invention, such disclosed meansand mode illustrating,howevenbut one of various ways in which the principle of the inventionmay be used. 7

In said annexed drawing Fig. 1 is a perspective View of a testingapparatus embodying my present improvements, said device. being shown asmounted in connection with the necessary chart; Fig. 2 is a sideelevation of one portion of the apparatus; Fig. 3 is-at-op planview ofthe same; and Fig. 4 is a top plan view of the test chart proper and ofthe holder therefor.

As indicated by the foregoing figures, the apparatus itself principallyconsists of a test chart 1, which may be of any suitable con struction,and an apertured plate or sheet 2 which is used before the eyes of theperson beingtested, the device being so arranged that it can readily beattached to any photooptometer or other. similar device.

In the illustrated form of the apparatus, a bar or rod 3 is provided onwhich such chart 1 and plate 2 can be adjustably mount ed in a mannersimilar to the usual testing apparatus. It will, however, be noted thatthe plate or card 2 is provided with two rectangular holes 4t and 5, asbest shown in Fig.

1, each of which is approximately 31 by (52 millimeters in size andsymmetrically spaced on opposite sides of a vertical center line betweenthe two and also on opposite sides of a. horizontal line therebetwecn.In other words, if the plate is considered a rectangle divided intoquarters by a horizontaland a vertical center line, the two rectangularopenings will be located in diagonally opposite quarters of the card.Vhile such openings lie close to the center lines, they do not quitetouch the same; the inner vertical edge of each opening being spacedapproximately 8 millimeters from the vertical center line and thehorizontal edges of the openings being spaced approximately the samedistance above and below the horizontal center line.

The plate through which the openingsare cut may be of any color, but ispreferably made a dead black and below the rectangular openmg 4: in theupper right hand quarter of the plate is a white portion or area 6,which is as wide as the opening and extends downwardly to a line passingthrough the upper edge of the other opening. Sii'i'iilarly, there is awhite area? above the opening in the lower left hand quarter of theplate of the same size, that is, of a width equal to the opening and ofa height to align with corresponding area 6 adjacent the lower edge ofthe other opening.

To one edge of plate 2 (the left as shown in Fig. 1) isattached a secondsmaller rectangular plate 8 of solid opaque material, such plate 8 beingpreferably enameled or colored white on one side and being used todetermine whether hyperphoria is present. While it is not essential thatthe smaller iii plate be thus attachedto the largertfor they I chart.

which is tittach'ed'to 't-he plateand ivhich encircles 'therbd so astohold the plate in'an'y desired adjustable position, said rod '10 beingprovided at its lowerend with'a'supporting member 12 which is in turnslidably mounted upon the horizontal bar 3.

A second supporting member 13, also slidably mounted on said horizdnta'lhar "carries a frame 14in which the test chart l maybe'removiiblynioiiiitell. This'test chartis divide'd 'up iiito quarters,the diagonally oppositequarters containing the's'anietestcharacters.Preferably thequarters into 'Which the chart is thusdivided areinarkedofi' 'by two fairly broad "black lines 15, "that cross each otherat right angles as hest'shown on Fig. 1. These lines ser've 'to carryout the testing io'r both lateral and vertical imbalance as will be more:EullydeScribedhere: in'afte'r.

a In use, the test plate 2 is Set in 'front of thepatients eyes so thatthea'ighteye looks through tlie rcetangiilar opening 4 in the upperright hand quarter of the plate and the left'eye'through thecorresponding'opening's in the lovverleft hand corner, and the testhart' l is se'tron thebar 3 at a suitable distance from the plate sotl1at "tlie patient sees ivith each eye "one half of the- Whole Thus theright eye sees the upper test types and astigmatic wheel or dial, while'the left'eye views the lower test types and the lower Wheel or dial. Asa result, ivhehthepatientis asked to reportthe readability ofthe uppertypes, he imagines he is seeing them with both eyes and hence puts fortha normal nervatio'nal effort and this same effect is also present whenis asked to read the lon'er types. This means that both eyes arevirtually examined at once, forthe patient can look fromdne chart tothe-other'and give a comparative report as to their distinct'nes's.

The rectangularopenings '4 and 5 inplate 2 are so arranged that'theupper half of the object or test chart is presented to the lower half ofthe macnla lutea of the right eye and the lower half of the object ortest chart is presented to the upper half-ofthe niacula lu'te'a of theleft eye, and thus, since each eye sees only half of the chart, thesight center of the brain will unite 'the two portions'fro'm 'thetwoeyes and asing'le image -will he the impression ohtained, providedthe eyes are orthopho'ric, i. e. innormalhalance. in casethe eyes arenot'orthophoric, the upper half image will appear to the right of thelower'half image in a case of esophoria, I and 'the X upper half of theimage will appearto theleft of the'lowerhalf of the iinageina 'case ofeXophoria. Therule also holds'good 'in cases'of hyperphoria or verticaliinba'lanc'e. In such cases, the left half'oft'he object isprese'nted tothe right sideof the maculaoftherighteye and the right hlilflof theobject it presented to the lett half of the inaculh "of the 'left eye,so that if no vertical imbalance exists, the twohalves oftheohject willbe presented to the sight centers as one single image of the test chart.However, if right hyperphoria exists, the half image of the right eyewill appear wane "riglitside, but lower than the half image on the left,and in the case of left hyperphoria, the image of the "left eye will 'a)pear on the left sidehllt lo'werflclown than he image on the oppositerifle. av an the phtierits eyes "have been 'test etl as this manner andit 'hasb een determined that anyof'the muscular in 'balanc'esarepres'eii t, that is, either esophoria m- "exophoria, or right or lefthyperphoriu, then the 'us'tml prism methods of correction for thesedefects may be employetl.

In a case of 'cyclophoria, the hlack lines ofthe rhart will notappelira'sitact veiftical or horizontal linesduring the test, hilt ivillappear at angles to each other. The angled line will represent the eyeafilited with this particular ailment ;'o1"if both eyes are thusalilictedboth ofthe hlaek lincs'iif the chart will appear distorted fromnmhial. Previous types of muscle tests for have depended wholl u on themihhturhl straining (if the functwn: powers o'Ftheextrinsic muscles "ofthe eyes and such tests are substantially intolerable if'coritihu'ed forany length of time and instead ofallaying disturbances, reallyaccentuate "them, and to this extent it in'a be said that their use isfaulty andobjecti'onable because they measurenot what the eyes'will doif allowell to seek a position'o't' physiological rest but Wh'aftheyaredoing under the stressfof inal functioning muscles.'Thepre'senttleviceinstead of producing diplopia or double images,\vholly retains thesingleness of the test ohject'and the use of thepresent "device does 'not tire the eyesor accentuate the malfunctioningof the muscles but actually rests them. This isbecause theentity-uf thetest chart or object is not interfered with and the involuntaryfaculties of binocular visionare not disturbed. Q

'As a matter of "fact, the-device ean'be left before "the eyesindefinitely without 'exci'ting the most sensitive person to request itsremoval; and it is best to alloiv itto remain throughout a completeexamination because the preliminary readin may be but the manifestationof a 'ps'eu o defect, Whiletlie last readingmfterdue re'st 'h'as heenallowed, is the true representation of the refil defect; For exampleyeaohoria that is due to overstimiilati'on of the sixth nerve to overcomeactual esophorimas sho'w'n 'atth'e'hegihning of the 't'est, will'paseover into trne'esophoric appearances at the close of the work'hecause in a 'stateof r'e'pos'e, tlre'third nerve stimuli to theinternal recti must rpredomi- 'gards the means and nate. Again, in thecase of esophoria due to overstimulation of the third nerve fromhyperopia, the application of correcting plus lenses will graduallycause the muscle disturbance to disappear, and the patient can beinstructed to state the relation of the test lines from time to timeduring a test, a thing never heretofore possible during a test, becauseall the older tests become intolerable after a very brief space of time.

In the illustrated form of the apparatus, it will be understood ofcourse that the patient may wear the usual trial frame or a trial framemay be supported on the bar 3 along with the other parts of theapparatus as in any phoropter, phoro-optometer or similar apparatus. Inplace of a small test chart 1 supported in close proximity to theapertured plate 2, an illuminated distant chart may be employed withletters and clock dial similarly arranged. The lettering on such distantchart will be the same as on chart 1 where it is to be viewed directlyor where on account of limited space available to the optometrist oroculist, a mirror is employed to reflect the chart to the patient, thetype will of course be required to be reversed.

()ther modes of applying the principle of my invention may be employedinstead of the one explained, change being made as rethe steps hereindisclosed, provided those stated by any of the following claims or theirequivalent be employed.

I therefore particularly point out and distinctly claim .as myinvention:-

1. In a. device fortesting eyes, the combination of duplicate sets oftest objects in diagonally located relation and means for causingopposite retinal halves of the re View respective sets.

2. In an eye testing device, the combination of a test chart havingduplicate test characters in diagonally opposite quarters, and a platewith sight holes, one for each eye and spaced apart vertically andhorizontally.

spective eyes to 3. In an eye testing device, the combina tion of a testchart divided into quarters and having duplicate sets of test charactersin diagonally opposite fourths, and a plate adapted to be interposedbetween the eyes to be tested and the chart and having two spacedapertures so positioned as to allow each eye to receive one half of one.set of test characters, the halves being opposite so that together theywill form a true complete image if no muscular imbalance is present inthe eyes.

4:. In an eye testing device, the combination of a test chart dividedinto quarters and having duplicate sets of test characters in diagonallyopposite fourths, and i a plate adapted to be interposed between theeyes to be tested and the chart and having two spaced apertures ofrectangular form, such apertures being spaced on opposite sides of botha horizontal and a vertical line and so positioned as to allow each eyeto receive one half of one set of test characters, the halves beingopposite so that together they will form a true complete image if nomuscular imbalance is present in the eyes.

5. In an eye testing device, the combination of a holder, a test chartmounted on said holder, said chart being divided into fourths by avertical and a horizontal line and being provided in diagonally oppositecorners with duplicate sets of test characters, 'a plate mounted on saidholder and movable relative to said chart and adapted to be positionedbetween the chart and the eyes to be tested, said plate having twospaced apertures ofrectangular form, such apertures being spaced onopposite sides of both a horizontal and a vertical line and sopositioned as to allow each eye to receive one half of one set of testcharacters, the halves being opposite so that together they will form. atrue complete image if no muscular imbalance is present in the eyes.

Signed by me this 12th day of March, 1925.

J OSEPH W. SMITH.

